Circuit breaker with trip indicator



y 1969 R. w. DUNHAM ETAL 3,443,258

CIRCUIT BREAKER WITH TRIP INDICATOR Sheet Filed Nov. 10, 1966 R. w.DUNHAM ETAL 3,443,258

May 6, 1969 CIRCUIT BREAKER WITH TRIP INDICATQR Filed Nov. 10, 1966Sheet 2 of 2 64 .93 7 Z5 2/ Z Z 3 A;

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2 WA 7'7'0E/VEX United States Patent US. Cl. 337-79 1 Claim ABSTRACT OFTHE DISCLOSURE The circuit breaker has a stationary contact, a movablecontact carrier, and a trip member which is normally latched inuntripped position by a current responsive trip mechanism and isreleased thereby under abnormal conditions. In untripped position, themovable contact carrier can be moved to open and closed positions by amanual operator. Upon tripping, the movable contact carrier is moved toopen position. An indicator is rockable about a fixed axis from anonindicating position to a trip indicating position. This indicator isdirectly connected to the trip member by a coil tension spring which iscaused to act in tension upon release of the trip member to rock theindicator to an indicating position and is caused to act in compressionupon movement of the trip lever to untripped position by the manualoperator to rock the indicator to a nonindicating position.

This invention relates to a circuit breaker having a trip indicatorwhich by a signal indicates that the circuit breaker has been tripped.

More particularly the invention relates to a visual indicator or flagwhich, when the circuit breaker is turned ON or OFF, but is in untrippedcondition, is displaced from a window in the housing of the breaker soas to be in a nonindicating position wherein it is not visible throughthe window. However, upon tripping of the breaker, whether due to amoderate and long sustained overload or sudden severe overload or fault,or for any reason the indicator is moved by a trip lever of the breaker,when the lever moves after being tripped or released, to an indicatingposition in which the indicator becomes visible through the window,thereby indicating the tripped condition of the breaker.

The arrangement of the indicator is such that, as in prior breakers,after the trip lever is set the breaker may be turned ON and OFF by amanual operator or handle without movement of the trip lever, and,therefore, without movement of the indicator out of its displaced ornonindicating position.

For the purposes of illustration, the trip indicator is shown asincorporated in a circuit breaker of the type fully described in UnitedStates Letters Patent No. 2,902,- 560 of Stanback et al., issued Sept.1, 1959, its use with other types of breakers employing trip leversbeing readily apparent from the illustrative example.

It is well known in the art, as evidenced by Green patent No. 2,222,312,issued Nov. 19, 1940, to provide an indicating flag biased toward an ONindicating position by a torsion spring and the like, and driven againstthe force of the spring by a contact arm into a tripped indicatingposition as the circuit breaker trips. In the breaker of this patent,the indicator or flag is not caused to move by manual operation of thecircuit breaker.

In Platz Patent No. 2,905,795, issued Sept. 22, 1959, a signal drum orflag is provided which indicates ON, OFF, OVERLOAD, TRIP, or SHORTCIRCUIT, by means of a drum biased by a torsion spring toward the OFFindicating position. Upon manual closure of the circuit breaker the drumis rotated to ON indicating position against the bias of the torsionspring by an extension on the contact arm. Upon tripping, the drum isreleased and the spring revolves to the appropriate one of the otherpositions, depending upon whether the magnetic trip responded to a shortcircuit or a bimetal responded to an overload. The drum, therefore, isoperated in direct response to the trip mechanism generally, and not inresponse to the trip lever, and operates manually in response tomovement of the contact arm.

From the above patents it is shown to have been known heretofore (a) tooperate an indicator of a circuit breaker by the usual bimetal of thetrip mechanism, by magnetic trip, by the manual operator, or by thecontact arm, and (b) to spring bias the indicator toward either ON orTRIPPED indicating position. However, it is new to use the trip lever ofa breaker in the manner disclosed herein for causing movement of anindicator for indicating the tripped condition of the breaker.

The principal feature of the present invention resides in the fact thatthe indicator or flag is arranged and connected to the trip lever so asto be moved from a nonindicating position into an indicating position bythe trip lever as the lever, upon being tripped, moves into a finaltripped position, and so as to be moved into nonindicating position bythe trip lever upon movement of the trip lever to its untripped positionby the manual operator of the breaker.

More specifically the invention relates to a flag which is pivoted inthe housing of the breaker in a position to swing into and out ofindicating position with respect to a window in the housing, and whichis connected to the trip lever of the breaker by an extensible linkwhich interconnects the flag and trip lever in a manner such that thelever, upon movement to untripped position, causes the link to push theflag out of indicating position, and upon movement of the lever totripped position, causes the link to pull the flag into indicatingposition. Preferably, the extensible and retractable link is a coilspring which is normally closed and in closed condition acts incompression as a rigid link to transfer movement of the trip lever tothe flag for moving the flag to nonindicating position as the trip leveris moved to untripped position, and which, in stretched or extendedcondition, acts in yieldable tension to transfer movement of the leverto the flag for moving the flag into tripped indicating position withrespect to the window when the lever moves to final tripped position.

Various other objects and advantages of the present invention willbecome apparent from the illustrative example wherein reference is madeto the drawings, in which:

FIG. 1 is a diagrammatic top plan view of a single pole breaker and flagindicator embodying the principles of the present invention;

FIG. 2 is a front elevation of the breaker illustrated in FIG. 1, withthe front cover removed and part of the manual operator being brokenaway for clearness in illustration, and showing the breaker parts andindicator in their relative positions when the breaker is ON anduntripped;

FIG. 3 is a right end elevation of the breaker illustrated in FIGS. 1and 2;

FIG. 4 is a fragmentary view similar to FIG 2, showing the relationbetween the indicator and certain parts of the breaker when the breakeris tripped; and

FIG. 5 is a view similar to FIG. 4 showing the relation of the indicatorand parts of the breaker when the breaker is OFF and untripped.

Referring to the drawings, as mentioned, the breaker itself is onedescribed in detail in US. Patent No. 2,902,560, and therefore is hereindescribed only briefly.

The breaker comprises a body or housing 1, of molded insulatingmaterial, closed at one face by a detachable cover 2. In the housing 1are a stationary contact 3 and a movable contact 4 which is mounted on acarrier 5. Pivotally mounted in the housing 1 is a manual operator 6having an external operating handle 6a. The upper end of the carrier isprovided with fingers 7 of which the upper ends engage in slots 8 in themanual operator 6 in rocking relation so that the carrier 5 can berocked clockwise and counterclockwise about the upper ends.

Also pivotally mounted in the housing 1 for rocking about a pivot 9parallel to that of the operator 6 is a releasably latchable trip lever10. The lever 10 is connected by a spring 11 to carrier 5. The spring 11urges the carrier 5 upwardly so as to seat and hold the upper ends ofthe fingers 7 in rocking contact with the walls of the slots 8. Thespring 11 also acts to rock the trip lever clockwise about its pivot 9when the trip lever is released by the trip mechanism of the breaker.The trip lever 10 has an actuating portion 12 which, when the trip leveris released and swings clockwise, engages a shoulder on the carrier 5and rocks the carrier 5 counterclockwise about the upper ends of thefingers 7 to open position.

The spring 11 has a dead center position and is arranged so that itbiases the carrier to contact making position when the lever 10 isuntripped. When the lever 10 is tripped, it swings clockwise and carriesthe upper end of the spring 11 past a dead center position, whereuponthe spring 11 moves the carrier 5 to fully open position while at thesame time still maintaining a downward force on the trip lever 10 urgingit to rotate in the clockwise direction.

In order to latch the trip lever in the untripped position, asillustrated in FIG 2, trip mechanism 14 is provided. The trip mechanism14 comprises a bimetal and blade assembly comprising a conducting strap15 connected to a terminal 16, and a bimetal member 17 fixedly connectedat its upper end to the strap and extending downwardly therefrom. Amagnetic yoke member 18 is connected to the lower end of the bimetal 17.A movable magnetic armature member 19 is pivotally cradled near itsupper end in arms 20 on the yoke member 18 and is held by an armaturespring 21 for yieldably resisted swinging movement relative to the yokemember 18. To the lower end of the magnetic armature is secured aU-shape ambient temperature responsive bimetal member 23. A conductor24, having a loop portion wound about a part of the magnetic yoke, isconnected at one of its ends to the bimetal member 17 and at the otherof its ends to the movable contact 4 by a flexible conductor.

Thus, upon a moderate sustained overload, the bimetallic member operatesto cause the magnetic yoke to swing counterclockwise, swinging with itthe magnetic armature 19. On the other hand, a sudden undue surge incurrent causes the armature 19 to swing counterclockwise. In eitherevent, the swinging action releases the trip lever 10.

In order to hold the trip lever in untripped position, it is provided atits outer end with a finger portion 26 which, at its lower edge, engagesan upwardly facing latching shoulder 19a disposed in a notch in thearmature 19 when the trip mechanism is in latching position, therebypreventing swinging of the trip lever 10 clockwise out of its untrippedposition. Upon movement of either the armature 19 or the yoke 18counterclockwise, the finger 26 is released and the spring 11 becomesoperative to swing the trip lever 10 clockwise.

The structure thus far described is that fully disclosed in the aboveStanback Patent No. 2,902,560.

As mentioned, in accordance with the present invention, the trippedcondition of the breaker is to be indicated. For this purpose a window27 is provided in the top wall of the housing 1 adjacent to the manualoperator. A suitable viewing lens 28 is mounted within the window. Inthe housing 1 adjacent to the window is a suitable pivot 29 on which ispivotally mounted an indicator 30. The indicator 30 comprises a body orrocker 31 which may be of sheet metal or molded composition. The rocker31 has a finger 32 extending radially therefrom partway of its lengthwith its outer end bent over to extend axially and provide an indicatoror flag 33. The outer face of the flag 33 faces the lens and preferablyis coated with red fluorescent paint. At the opposite side of thepivotal axis, rocker 31 is provided with a fin 31a having an aperturetherein through which one end of a spring 34 is received for connectingthe spring to the rocker. The opposite end of the spring 34 is receivedin a suitable aperture 35 in the trip lever 10 for connecting the spring34 thereto.

The spring 34 is so chosen that it is normally in unstressed conditionand sufiiciently still to act as a compression link. For example, it maybe a normally closed coil. On the other hand, it can be resilientlyextended endwise and act under tension. Thus the spring 34 operates asan extensible and contractible link pivotally connected at its oppositeends to the indicator rocker 31 and trip lever 10, respectively.

When the breaker is ON and the trip lever is in untripped condition, theflag 33 is held in a position out of alignment with the window 27 andlens 28 by the trip lever acting through the spring 34.

Assuming the breaker has been tripped, for resetting it the lever 10 isswung counterclockwise to latched position by moving the manual operator6 from an intermediate TRIPPED position, as shown in FIG 4, to OFFposition, as shown in FIG. 5. As the lever 10 is thus swungcounterclockwise, the spring 34 acts as a compression link and rotatesor rocks the rocker 31 counterclockwise to dispose the flag 33 innonindicating position out of alignment with the window 27, asillustrated in FIG. 5. This relation continues whether the manualoperator 6 is left in OFF position or is moved to and from OFF and ONpositions.

On the other hand, when the breaker is ON, as shown in FIG. 2, and thetrip lever 10 is released, it is rocked in a clockwise direction by thespring 11 to the position shown in FIG. 4. The spring 34 then operatesas a resiliently extensible link, and becomes operative to transmit themovement of the lever 10 to the rocker 31 so as to rock the rocker 31about its axis in a clockwise direction to a position wherein the flagis beneath and visible through the window 27 and lens 28. The finger 32of the rocker 31, when the flag is in this position, engages a suitableshoulder 36 in the housing so as to stop the flag precisely in thedesired position when moving in a clockwise direction. Thereupon, thespring 34 can elongate suificiently to hold the flag 33 visibly in theindicating position while permitting the lever 10 to continue on, underthe influence of the spring v11, to final tripped position.

The trip lever carries a reset pin 37 which, when the trip lever is intripped condition and the manual operator 6 is rocked in a clockwisedirection from an intermediate TRIPPED position (FIG. 4) to the OFFposition (FIG. 5), is engaged and moved by a portion of the manualoperator 6 and thereby swings the trip lever 10 counterclockwise to thelatching position. While in this latched, untripped position, with thelatching lever 10 holding the flag 33 out of alignment with the window,the manual operator 6 is then rocked counterclockwise to ON posi tion(FIG. 2) and thereby swings the fingers 8 beyond the dead centerposition of the spring 11, thus causing the spring 11 to move thecarrier 5 to contact making or ON position.

During this operation of the manual operator 6 to ON position, the triplever 10' remains fixed in its untripped position, wherein the flag 33is not visible through the window 27, so that the breaker can be turnedOFF and ON by the manual operator 6 without causing the flag to becomevisible through the window.

Having thus described our invention, we claim: 1. An electric circuitbreaker comprising:

a housing;

a stationary contact in said housing;

a movable contact carrier in said housing;

tending as said trip lever moves fully to tripped position to move saidindicating portion into alignment with said window and to hold theindicating portion in alignment with said window so long as the triplever remains in fully tripped position; and

a movable contact mounted on said carrier and movable 5 the distancebetween the points of connection of said thereby into and out ofengagement with said stalink with the trip lever and the indicatingmember, tionary contact; respectively, being equal to the length of theunexa releasably latchable trip lever pivotally mounted in tended linkwhen the trip lever is in said latched said housing and releasable froma latched position 10 position and the indicating member is positionedwith for movement to a tripped position to effect sepaits indicatingportion out of alignment with said ration of said contacts; Window.

a window in said housing; References Cited an indicating memberpivotally mounted in said hous- UNITED STATES PATENTS ing and having anindicating portion movable into alignment with said window upon movementof said 2,367,382 1/1945 Taylortrip lever to said tripped position andmovable out 25851011 7/1954 Boner et of alignment with said window uponmovement of 2,055,183 9/1936 Sperrysaid trip lever to said latchedposition; FQREIGN PATENTS an eXtensible-contractible link connectingsaid indicat- 657,744 2/1963 Canada.

ing member and trip lever and acting as a solid member in compressionwhile pivoting said indicating member to move said indicating portionout of alignment with said window as said trip lever moves from saidtripped position toward and to said latched position and acting as anextensible member and ex- BERNARD A. GILHEANY, Primary Examiner.

R. L. CO HRS, Assistant Examiner.

